How to Change the Machine ID in XP
In Windows XP, the "Machine ID" is the name your computer identifies itself by on a network. When you installed Windows XP on your computer, you chose a "name" for your computer during the install process, and this in turn became the machine ID. Sometimes, however, the name one chooses for the computer during the install ceases to be appropriate--don't want your boss seeing 'TehPwnzorComputor' on the office network, for instance--and a change needs to be enacted. Fortunately, Windows XP has made it easy to change the name of your computer.
Turn on your computer and allow Windows XP to load normally.
Click the start menu and select "Control Panel."
Scroll down until you find the "system" icon. Double-click the icon.
Click the "Computer Name" tab in the new window that appears.
Click the "change" button. A new window will appear asking you to input the computer's new name. Do so, and then click "OK". You have now successfully changed your computer's machine ID.